Fiber optics are increasingly used for transmitting voice and data signals. Generally, however, the data carried by light signal must be converted to an electrical format when received by a device, such as a network switch. Conversely, when data is transmitted to the optical network, it must be converted from an electronic signal to a light signal. Typically, an optical transmitter, receiver or transceiver module is electrically interfaced with a host device such as a host computer, switching hub, network router, switch box, and the like via a compatible connection port. Certain international and industry standards have been adopted that define the physical size and shape of optical transceiver modules to insure compatibility between different manufacturers. For example, in 1998, a group of optical manufacturers developed a set of standards for optical transceiver modules called the Small Form-factor Pluggable (“SFP”) Transceiver MultiSource Agreement (“MSA”). In addition to the details of the electrical interface, this standard defines the physical size and shape for the SFP transceiver modules, and the corresponding host port, so as to insure interoperability between different manufacturers' products. The standard also specifies that the module be hot-pluggable, that is, that it may be removed or inserted while in operation. Although the industry standard specifies a minimum amount of space between host ports, so that transceiver modules can be individually accessed and removed from the host device without disturbing the adjacent modules and/or cable connections, there is often a desire to provide configurations having a higher port density.
To provide for higher port density while maintaining other aspects of the SFP design of the MSA standard, an integrated latching mechanism has been proposed in U.S. Pat. No. 6,533,603 in the name of Togami. In the module apparatus taught by Togami, the latch mechanism is operated by way of a moveable bail lever that is moveable between two positions, which in turn dictate the position of a locking pin. When placed in a latched position, the locking pin extends from the module and engages with a corresponding recess within a host port, causing the module to be latched and secured within the port. When the bail is moved to an unlatched position, the locking pin is disengaged from the locking recess, which permits the module to be extracted from the port. In the apparatus taught by Togami, movement of the locking pin by way of the bail is accomplished with a cam portion that is integrated with the bail lever. Rotation of the bail causes manipulation of the cam, which in turn operates against a cam follower surface formed on a pivot block which carries the locking pin and that has pivot arms that are held within pivot points on the top surface of a connector portion. When in the latched position, the cam is disengaged from the cam follower surface, and a biasing means formed on the housing urges the pivot block to rotate the locking pin into the latched position. In the unlatched position, the cam forces the pivot block to rotate the locking pin so that it is disengaged from the locking recess.
Although the latch mechanism of the aforementioned Togami apparatus appears to perform its intended function adequately, it, disadvantageously, requires a pivot block and an associated pivot-point means of attachment of the pivot block to the connector portion of the module. The need for a pivot block and its associated means of attachment adds complexity and cost to the latching mechanism and occupies volume within the module. Unfortunately, the total volume available within a module may be severely constrained and, in such a situation, the need for the pivot block for latching purposes causes the space available for other critical components to be reduced.
Because of these aforementioned disadvantages of the latching mechanism of the prior art, there is currently a need for a latchable optical and electronic module, such as an optical transceiver module, having a simple latching mechanism that does not require a pivot block but that, nonetheless, permits maximum port density, maintains compliance with the mechanical dimensions of existing industry standard modules, permits the module to be easily inserted and extracted from a port without disturbing the communications link of adjacent modules and that provides a means for simple extraction or insertion of the module. The present invention addresses such a need.